Carb Woes

Wed Jan 09, 2013 4:01 pm

Hi all...

I have been talking with a local member via PM about their cub. One issue that came up was that a recently rebuild carb LEAKS after less than 10 minutes after opening up the fuel bowl. The person used the "deluxe" rebuild kit (not Tisco, I believe). Replaced needle valve, seat, soaked in carb cleaner, cleaned out all passages, etc, but still, after buttoning it back up, it leaks. He even put his old seat and needle valve back in the tractor and STILL has leaks. The replacement needle valve has the dreaded Viton tip, but it is NOT sticking yet. He has kept the valve and the seat as a set. Float is NOT leaking and has no fluid in it. He is confirming float height, but said he believed it was correct.

I talked with him about potentially using some valve lapping compound and lapping the original needle valve and seat together to try to get a good seal.

The reason for this thread is just to vent. I have had similar problems on a rebuilt carb on Merlin (done by one of the carb gurus" when I got the tractor originally). My leak is not rapid, but it still leaks. My problem is compounded by the fact that the valve on my fuel bowl is apparently bad as well, so I can't stop my little drip! The vent is that you would think that such a simple little carb would be easily repaired and would not be so prone to problems as this one is!

Re: Carb Woes

Wed Jan 09, 2013 4:11 pm

Hose barb to fit carb inlet, clear plastic tubing to match the hose barb, funnel small enough to fit inside the clear plastic tubing and a bottle of rubbing alcohol from the dollar store.

Remove carburetor top, turn and block upside down on bench with hose barb, tubing and funnel attached. Funnel above carburetor, fill with alcohol. Observe needle valve area and remainder of carb top for source of leakage.

Re: Carb Woes

Wed Jan 09, 2013 4:20 pm

Had a few act like that over the years. found out the gasket between the two halves of the carb was rubbing on the float keeping the float from closing the needle valve properly. also had two carbs over the years with hair line cracks where the needle seat screws in.

Re: Carb Woes

Wed Jan 09, 2013 4:58 pm

There are some suggestions in this thread.

Re: Carb Woes

Thu Jan 10, 2013 10:47 am


Hengy wrote:My problem is compounded by the fact that the valve on my fuel bowl is apparently bad as well, so I can't stop my little drip!

The fix for that is twofold.

#1. Repack you valve. Not too difficult. Should last for a long time when done correctly.

#2. Replace that valve with a ball valve. Poof :shock: no more problems. :idea: :) Since I replaced Ellie's I have not had a leak from my fuel sediment bowl valve, period.

It isn't exactly an original part but then again neither is the new gas cap. Just makes sense, at least to me.